Digital electronic control circuit for cyclically operable appliances and the like

ABSTRACT

An electronic digital control system for automatic appliances and the like of the type capable of carrying on one or more cycles, each cycle comprising a plurality of sequential operations, each operation in turn comprising a plurality of events in sequence performed by a number of on-off machine devices or functions. The control system comprises a control logic circuit which performs logical operations on inputs from a source of regularly spaced electrical pulses, sensors, and panel switches of the appliance; and generates outputs which, either directly or by means of interfacing devices, activate and deactivate the machine functions in a desired time sequence and/or in accordance with a desired control strategy based on criteria other than time, by controlling the power to the machine functions.

United States Patent Sample et al.

[ DIGITAL ELECTRONIC CONTROL CIRCUIT FOR CYCLICALLY OPERABLE APPLIANCES AND THE LIKE [75] Inventors: Steven B. Sample; Paul R. Scheuer;

Stevan W. Speheger; Karmen D. Cox, all of Lafayette, Ind.

[73] Assignee: Design and Manufacturing Corporation, Connersville, Ind.

[22] Filed: Apr. 29, 1971 [21] Appl. No.: 138,625

[ Nov. 20, 1973 3,548,203 12/1970 Basse et a1. 328/48 X 3,639,844 2/1972 OTHER PUBLICATIONS A Digital IC Timer by Steinbach in Electronics World dated May 1969, Pages 48-50.

Primary Examiner-Stanley D. Miller, Jr. Attorney-Melville, Strasser, Foster & Hoffman 5 7 ABSTRACT An electronic digital control system for automatic appliances and the like of the type capable of carrying on one or more cycles, each cycle comprising a plurality of sequential operations, each operation in turn comprising a plurality of events in sequence performed by a number of on-off machine devices or functions. The control system comprises a control logic circuit which performs logical operations on inputs from a source of regularly spaced electrical pulses, sensors, and panel switches of the appliance;

[56] References Cited and generates outputs which, either directly or by UNITED STATES PATENTS means of interfacing devices, activate and deactivate 2,970,226 1/1961 Skelton et al.... 307/293 the machine functions in a desired time sequence and- 3,383,525 5/1968 Arksey 8/ 9 X /or in accordance with a desired control strategy Huxster 6t based on criteria other than time controlling the 3,409,761 11/ 1968 Becker 328/46 X power to the machine functions. 3,464,673 9/1969 Cargo et a1. 134/57 D X 3,539,153 11/1970 Wennerberg et a]. 134/57 D 72 Claims, 26 Drawing Figures 1 +25 545: 7 2/6741. CAOCK V 5 C I l I i 4 2 3 I F 7 l l i i /Z6 i 67/64 may l DECOO/A/G 106/6 i A 06/6 I l i l i I I I u a o u a l 1 I I l l i I FUA/CT/Ot/ 00/1/7602 i I 1 l l LOG/C i l g i L J I LFL'IL i I 25 HECT/P/CAL WEEFAf/MG DEV/(IE5 30 J| IDOWE/E L O I a Pmmmnuvzo 1.91s 3; 774' 05s SHEET 08 0F 17 I I u e m m 2% M W S n m WW n J m m W IMMM. E 9% n X n w w a w. W K

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ATTORNEYS DIGITAL ELECTRONIC CONTROL CIRCUIT FOR CYCLICALLY OPERABLE APPLIANCES AND THE LIKE BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to an electronic digital control system and its appurtenances, and more particularly to such a control system for an appliance or the like of the type having a plurality of devices capable of performing a plurality of operations in one or more predetermined sequences.

2. Description of the Prior Art For purposes of 'an exemplary showing, the control system of the present invention will be described as applied to a dishwashing machine. A dishwashing machine is typical of the general class of appliances or the like to which the control system of the present invention may be advantageously applied. It will be understood by one skilled in the art, upon reading this specification, that the control system of the present invention may be applied to any'suitable appliance capable of performing a number of sequential operations, and its description with respect to a dishwashing machine is not intended to be limiting.

In present day dishwashing machines, the various operations are controlled or initiated by electrical means. A dishwashing machine generally comprises a vat having a front or top opening with a suitable closure means. There is ordinarily an electric motor which drives one or more pumps, and which often drives an impeller for showering the tableware in the vat with water. In many such machines a pump is employed of such character as to result in circulating the water when the motor is driven in one direction, and draining the vat when the motor is driven in the opposite direction. The dishwasher generally contains additional electrically operated elements, which may be varied as to number and kind, but which may include (without limitation) such elements as a heater, solenoid operated valves, a general illuminant, indicator means and solenoid operated means for injecting surface-active or other substances into the vat. The nature and function of these various means are well known in the art and do not constitute a limitation on the present invention. Thus, for convenience, these various elements will hereinafter be referred to as the machine functions." It will be noted that the various machine functions are generally of the on-off type.

Automatic dishwashers are arranged to carry on a plurality of operations, through the agency of the various machine functions, in sequence. The sequential series of operations is generally referred to as a cycle. For example, a typical automatic dishwasher is arranged to carry on in sequence a cycle of operations which may be designated as first wash, first rinse, second rinse, second wash, third rinse, fourth rinse, and dry.

Each of the above listed operations will, in turn, comprise one or more events. For example, the first rinse operation may be made up of the following exemplary events: pause, fill, spray, pause and drain. Therefore each cycle may be thought of as simply comprising a plurality of sequential events. The grouping of events into operations is strictly a matter of convenience.

The carrying on of this orsome other cycle of operations has heretofore been controlled by a timer of which various varieties are known. In general, the timer comprises a motor. In some instances, the motor drives a device like a commutator which results in sequential, and in some instances simultaneous, opening and closing of electric switches. In other instances, the timer motor drives a rotating element providing a plurality of camming surfaces for operating electric switches. The switch operating devices of some timers are arranged to be driven at a constant speed during the operation of the dishwasher. In other instances, the switch operating mechanism is arranged to be advanced step-wise.

At times, the operator of the dishwashing machine may desire to have the appliance carry through less than the full gamut of operations making up the most complex cycle of which the machine is capable. For example, it may be desired to place breakfast dishes in the dishwasher and give them a preliminary wash or rinse or both, reserving the full cycle of operations for a time when luncheon or perhaps dinner dishes may also be placed in the tableware racks of the appliance. To accomplish this, a knob is often affixed to the timer shaft so that the timer can be manually rotated through a portion or portions of its path of travel, thus lay-passing certain of the appliance operations. In other instances, a rapid advance motor is provided, to rotate the timeractuated switch operating mechanism at a rapid rate through one or more portions of the cycle. The rapid advance motor can be manually actuated, and is sometimes made actuable by the timing device itself so that certain portions of the cycle can be automatically omitted.

The prior art embodiments of the general types described above are capable of satisfactory operation, but have a number of distinct disadvantages. For example, in some instances the timer has to be located adjacent the manually actuable dial and knob so that the timer placement within the appliance is limited. In other instances, the operator has to manipulate a large number of push buttons, switches or the like in order to obtain the desired cycle. These various hand-manipulated devices tend to detract from the asthetic appearance of the appliance. In addition, the appliance controller, being essentially mechanical in nature, is subject to wear and adjustment problems.

Recently, prior art workers have attempted to overcome these disadvantages through the use of solid state control systems. US. Pat. No. 3,464,673 is exemplary of such a system. However, such a system is dependent upon an RC analog timer circuit which is relatively expensive, is relatively inaccurate, is subject to aging and does not lend itself well to integrated circuit techniques. In addition, this system employs a ring counter and a stepping switch which are relatively inefficient from a logic standpoint. The logic for this system is implemented by means of elements which are relatively expensive and do not lend themselves well to integrated circuit techniques. Finally, such a system is limited in its application and does not lend itself well to extension to more complicated control strategies.

The electronic digital control system of the present invention is adapted to provide a versatility hitherto unobtainable; to eliminate the disadvantages enumerated above; and to provide the advantages charteristic of electronic devices. For example, the control system of the present invention permits greater complexity and sophistication, greater reliability, lower cost, and is not subject to aging. In addition, the control system elements may now be located near the machine functions they control. Finally, the control system of the present invention facilitates controlling an appliance cycle on the basis of outputs from a number of low-power remote sensors, as opposed to controlling the cycle solely on the basis of elasped time.

SUMMARY OF THE INVENTION The control system of the present invention is particularly adapted to control the actuation of a plurality of machine functions in a cyclical or sequential manner such that during one cycle, any of the machine functions, or any combination of them, will be repeatedly turned on and/or off at certain predetermined times, or when externally applied signals reach certain predetermined levels. The control system comprises a control logic circuit which, through appropriate interfacing devices (when needed), controls the power to the various machine functions in desired order.

In its most basic form the control system of the present invention comprises a source of regularly spaced electrical pulses which drives a master counter in the form of a digital counter. The invention further includes a strategy logic comprising a decoding logic and a function control logic. Some or all of the outputs of the stages of the master counter are connected to the inputs of the decoding logic which partially or completely decodes some or all of the logical states of the master counter. The outputs of the decoding logic are connected to the inputs of the function control logic. The function control logic has a function control output for each unique machine function. It operates on the outputs of the decoding logic so as to provide a logical one at each function control output during those states of the master counter when it is desired that the corresponding machine function be actuated, and a logical zero at that function control output during all other states of the master counter. The function control outputs are connected directly to their respective machine functions or, where needed, through appropriate interfacing devices.

Of the above listed elements, the decoding logic and function control logic comprise the strategy logic which, combined with the master counter, comprises the control logic for the control system of the present invention. The system will further include means for providing power for the control logic, the machine functions and, if necessary, the interfacing devices. In instances where a machine function may be powered directly from the control logic an interfacing device need not be used.

In one specific embodiment of the control system of t the present invention a source of regularly spaced electrical pulses drives a master counter comprising a frequency divider and an events control counter. Some or all of the outputs of the stages of the events control counter are connected to the strategy logic comprising a decoding logic and a function control logic. The decoding logic comprises a plurality of event initiating gates. The function control logic comprises a plurality of activation and deactivation gates and a function control flip-flop for each unique machine function. In this embodiment there is one event initiating gate corresponding to the beginning of each elementary event in the cycle. The event initiating gates drive the inputs of the activation and deactivation gates, which in turn drive the function control flip-flops. The function control flip-flops control the machine functions through interfacing devices or, where possible, directly.

In another embodiment of the invention, the source of regularly spaced pulses drives a master counter comprising a frequency divider and an events register. There is one state of the evnts register corresponding to each event in the cycle. Some or all of the outputs of the stages of the events register are connected to the strategy logic, again comprising a decoding logic and a function control logic. The decoding logic comprises a plurality of event decoding gates. The outputs of the event decoding gates are connected to the function control logic comprising a plurality of function control gates. These last mentioned gates control the machine functions through interfacing devices or (where possible) directly. Period control logic and period select logic are also provided in this embodiment whereby the event outputs of the event decoding gates may also set the period of the frequency divider portion of the master counter to the particular value desired for each event.

In yet another embodiment the source of regularly spaced pulses drives a master counter, again comprising a frequency divider and an events register. Again decoding logic and function control logic (comprising a strategy logic) are provided, the function control logic controlling the machine functions through interfacing devices where such devices are required. This embodiment is adapted to take advantage of the fact that a number of events are repeated a number of time during a cycle. Thus the decoding logic is so designed that the first number of stages of the events register comprise a repeated events register and the remaining stages of the events register comprise an operations register. This embodiment is further provided with state select logic, preset logic, period control logic, reset control logic, pulse source interrupt logic, overfill protection logic, etc, as will be described hereinafter.

As suggested above, the control system of the present invention may incorporate a number of special features, applicable to all of the embodiments of the logic control circuit. One such feature is a pulse source interrupt, whereby control of the appliance may be relinquished to external sensors or signals. Means may be provided whereby the rate of advance of certain stages of the master counter can be increased so that, for example, the duration of a cycle may be shortened. Means may also be provided whereby the digital counter may be made to instantaneously assume any one of a number of predetermined states.

Finally, the invention contemplates the provision of efficient means for implementing the digital control logic; for providing power to the control logic; for interfacing between the control logic and the various machine functions where necessary; and for starting and stopping the control system.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of the overall control system of the present invention.

FIG. 2 is a diagrammatic representation of the basic embodiment of the control system of the present invention.

FIG. 3 is a logic diagram illustrating another embodiment of the control system of the present invention.

FIG. 4 is a logic diagram illustrating another embodiment of the control systemof the present invention. 

1. An electronic digital control system for automatic appliances and the like of the type having a plurality of on-off machine functions to be activated and deactivated in accordance with a control strategy comprising one or more cycles made up of a plurality of events, said control system comprising a source of continuous, equally spaced electrical pulses and a control logic, said control logic comprising a master counter and a strategy logic, said master counter having a plurality of stages, said stages having outputs, said strategy logic comprising a decoding logic to select and decode those states of the master counter relevant to said control strategy and a function control logic to interpret said selected states of said master counter and to control said machine functions in accordance with said control strategy, said decoding logic and said function control logic both having inputs and outputs, said pulse source being connected to said master counter, said inputs of said decoding logic being connected to some at least of said stage outputs, some at least of said outputs of said decoding logic being connected to some at least of said inputs of said function control logic, some at least of said outputs of said function control logic being connected to said machine functions, whereby said master counter is caused to change its state by pulses from said pulse source and said machine functions are activated and deactivated by said function control logic in response to said states of said master counter as selected and decoded by said decoding logic in accordance with said control strategy.
 2. The structure claimed in claim 1 wherein said control logic includes protection logic and wherein a sensing means for sensing appliance condition is connected to said protection logic, said protection logic being operative to preset said master counter to a predetermined state after a predetermined length of time has elapsed upon receipt of a signal from said sensing means and said protection logic being further operative to maintain said counter in a subsequent predetermined state after said preset operation has been effected.
 3. The structure claimed in claim 1 including preset means coupled to said master counter by which any predetermined number of said stages of said master counter may be made to instantly selectively assume logical one or logical zero.
 4. The structure claimed in claim 3 wherein said preset means is further connected to outputs of some at least of said master counter stages to be preset whereby said preset means is activated by signals derived from said last mentioned master counter stages, delaying means connected between said stage outputs and said preset means whereby said master counter stages to be preset are properly preset before said actuating signal disappears.
 5. The structure claimed in claim 1 wherein said appliance comprises a dishwashing machine.
 6. The structure claimed in claim 1 including means responsive to a signal from a source external of said means and interposed between said pulse source and said master counter to interrupt the transmission of pulses from said pulse source to said master counter for the duration of said signal, thereby inhibiting any change in state of said master counter for the duration of said signal.
 7. The structure claimed in claim 1 including reset means connected to said master counter by which any predetermined number of said stages of said master counter may be instantly reset to logical zero.
 8. The structure claimed in claim 7 wherein said reset means is further connected to outputs of some at least of said master counter stages to be reset whereby said reset means is actuated by signals derived from said last mentioned master counter stages, delaying means connected between said stage outputs and said reset means whereby said master counter stages to be reset are properly reset before said actuating signal disappears.
 9. The structure claimed in claim 1 including means connected to said master counter for bypassing at least one of said stages of said master counter.
 10. The structure claimed in claim 1 including a source of power for said control logic, said source of power for said control logic comprising a non-inductive DC power supply.
 11. The structure claimed in claim 10 wherein said DC power supply comprises a power supply providing a first voltage and a second voltage.
 12. The structure claimed in claim 11 including means within said DC power supply for delaying the establishment of said second voltage with respect to the establishment of said first voltage.
 13. The structure claimed in claim 11 wherein said DC power supply comprises a diode, a first resistor and a capacitor in series connection with a source of line voltage, a second resistor and a first zener diode connected together in series, said series connected second resistor and first zener diode being connected across said capacitor, a third resistor and a second zener diode connected in series, said series connected third resistor and second zener diode being connected across said capacitor, the voltage across said capacitor minus the voltage across said second resistor being greater than the break-over voltage of said first zener diode, said voltage across said capacitor minus said voltage across said third resistor being greater than the break-over voltage of said second zener diode, the voltage across said first zener diode comprising said first voltage, the voltage across said second zener diode comprising said second voltage.
 14. The structure claimed in claim 13 wherein said first voltage is higher than said second voltage and including means for delaying the establishment of said second voltage with respect to the establishment of said first voltage, saId means comprising a second capacitor connected in parallel with said second zener diode, said second voltage comprising the voltage across said second capacitor, whereby said second voltage will be delayed with respect to said first voltage by the amount of time required to charge said second capacitor.
 15. The structure claimed in claim 13 wherein said first voltage is higher than said second voltage and including means to delay said second voltage with respect to said first voltage, said means comprising a fourth zener diode so connected in series with said third resistor and said third zener diode that said second voltage will appear across said third zener diode after the break-over level of said fourth zener diode has been reached, said fourth zener diode being chosen to have a break-over level equal to said first voltage.
 16. The structure claimed in claim 1 including a source of line voltage, said pulse source comprising a circuit to attenuate and rectify said line voltage.
 17. The control system of claim 1 including a source of AC line current, said pulse source comprising circuit means to attenuate and rectify said line current, a master switch, said pulse source being connected to said source of line current through said master switch, interfacing means in said connections between some at least of said machine functions and the outputs of said strategy logic, said source of line current comprising a source of power for said some at least of said machine functions via said master switch and said interfacing means, a DC power supply connected to said source of line current through said master switch, said DC power supply comprising a source of power for said control logic.
 18. The structure claimed in claim 17 including a safety switch in said connections between said master switch and said pulse source and between said master switch and said machine functions.
 19. The structure claimed in claim 1 including a source of power for said control logic comprising a DC power source, at least one of said machine functions comprising a high current machine function, a source of AC voltage comprising a power source for said high current machine function, interfacing means connected between said high current machine function and its respective function control logic output, said interfacing means comprising a high current bidirectional thyristor and a lower current sensitive-gate bi-directional thyristor, said high current machine function being connected to said AC source via said high current bidirectional thyristor, the gate of said high current thyristor being connected to the load terminal of said low current thyristor, the gate of said low current thyristor being connected to said last mentioned function control logic output.
 20. The structure claimed in claim 19 wherein said control logic is implemented in the form of an MOS integrated circuit, said low current thyristor being controlled directly by said MOS integrated circuit.
 21. The structure claimed in claim 1 including preset means connected to said master counter by which any desired number of stages of said master counter may be made to instantly selectively assume logical one or logical zero, reset means connected to said master counter by which any desired number of said stages of said master counter may be instantly reset to logical zero, a source of line current, a DC power supply connected to said line current, a master switch in said connection between said line current source and said DC power supply, a plurality of non-corrective cycle select pushbuttons by which selectable ones of said cycles of said control strategy may be chosen for performance by said appliance, said non-corrective cycle select pushbuttons having outputs connected to said control logic, said DC power supply comprising the power source for said control logic and said non-corrective cycle select pushbutton outputs, a start-pulse generator connected to said DC power supply, the output of said start-pulse generator being connected to said control logic to activate said preset and reset means in accordance with the output of any selected one of said non-corrective cycle select pushbuttons upon closure of said master switch, means connected to said start-pulse generator for maintaining said start-pulse until said DC power supply has reached its minimum acceptable output for operation of said control logic, and means connected to said master switch for automatically opening said master switch upon completion of a cycle.
 22. The structure claimed in claim 21 wherein said start-pulse generator comprises a delay circuit and an inverter, the input of said delay circuit being connected to said DC power supply, the output of said delay circuit being connected to the input of said inverter, the output of said inverter comprising said start-pulse, said delay circuit being chosen to have a delay time sufficient to assure that said DC power supply has reached said minimum acceptable output.
 23. The structure claimed in claim 21 wherein said DC power supply provides a first and a second voltage, means in said DC power supply for delaying the establishment of said second voltage with respect to the establishment of said first voltage, said first voltage comprising the power for a part at least of said control logic and the outputs of said cycle select pushbuttons, said second voltage comprising the power for the remainder of said control logic, said start-pulse generator comprising an inverter the input of which is connected to said second voltage, the output of said inverter comprising said start-pulse, said delay means in said DC power supply comprising said means for maintaining said start-pulse until said first voltage of said DC power supply has reached said minimum acceptable output.
 24. The structure claimed in claim 21 wherein said non-corrective cycle select pushbuttons are mutually exclusive, and means whereby depression of any one of said cycle select pushbuttons results in closure of said master switch.
 25. The structure claimed in claim 24 including a cancel cycle pushbutton, said cancel cycle pushbutton being mutually exclusive with said non-corrective cycle select pushbuttons, a normally closed switch between said DC power supply and said start-pulse generator, said cancel cycle pushbutton being operatively connected to said normally closed switch to momentarily open said normally closed switch upon depression of said cancel cycle pushbutton, whereby to initiate a start-pulse upon depression of said cancel cycle pushbutton while said master switch is closed.
 26. The structure claimed in claim 1 wherein said master counter is separated into a frequency divider and an event control counter, the output of said frequency divider being connected to the input of said event control counter such that said event control counter advances its state by one each time said output of said frequency divider exhibits a logical one-zero transition, said frequency divider having a period such that the duration of every one of said events of said control strategy is an integral multiple of said period, the total number of said states of said event control counter being at least equal to the maximum number of said periods comprising the duration of any of said cycles of said control strategy, said decoding logic having a separate output corresponding to each separate event of said control strategy such that any given output of said decoding logic exhibits a logical zero-one transition only at the beginning of its corresponding event, said function-control logic comprising a function-control flip-flop for each machine function and means for setting and resetting each of said flip-flops, the output of each of said function-control flip-flops being connected to its respective machine function, the inputs of said setting and resetting means being connected to appropriate ones of the outputs of said decoding logic, whereby said machine functioNs will be activated and deactivated at the proper times and in the proper sequence in accordance with said control strategy.
 27. The structure claimed in claim 26 including reset means by which a predetermined number of said stages of said frequency divider can be immediately reset to logical zero, said reset means being connected to outputs of some at least of said stages of said frequency divider whereby said reset means generates a reset signal in response to signals from said last mentioned stages of said frequency divider to shorten the period of said frequency divider, delay means responsive to said reset signal for properly resetting said frequency divider stages before said actuating signal disappears.
 28. The structure claimed in claim 26 including means for varying the period of said frequency divider, said means comprising means for bypassing at least one of said stages of said frequency divider.
 29. The structure claimed in claim 28 wherein said means for bypassing said at least one of said stages of said frequency divider is activated in part at least by the state of at least one of the succeeding stages of said frequency divider.
 30. The structure claimed in claim 26 including preset means coupled to said master counter by which any predetermined number of said stages of said master counter may be made to instantly selectively assume logical one or logical zero.
 31. The structure claimed in claim 30 wherein said preset means is connected to outputs of some at least of said master counter stages to be preset whereby said preset means is activated by signals derived from said last mentioned counter stages, delaying means between said stage outputs and said preset means whereby said master counter stages to be preset are properly preset before said actuating signal disappears.
 32. The apparatus claimed in claim 26 wherein said appliance comprises a dishwashing machine.
 33. The structure claimed in claim 26 including means responsive to a signal from a source external of said means and interposed between said pulse source and said master counter to interrupt the transmission of pulses from said pulse source to said master counter for the duration of said signal, thereby inhibiting any change in state of said master counter for the duration of said signal.
 34. The structure claimed in claim 26 including means responsive to a signal from a source external of said means and interposed between said pulse source and said master counter to interrupt the transmission of pulses from one stage of said master counter to the next stage of said master counter for the duration of said signal, thereby inhibiting any change in state of said next stage and any succeeding stages of said master counter for the duration of said signal.
 35. The structure claimed in claim 26 including reset means coupled to said master counter by which any predetermined number of said stages of said master counter may be instantly selectively reset to logical zero.
 36. The structure claimed in claim 35 wherein said reset means is connected to outputs of some at least of said master counter stages to be reset whereby said reset means is actuated by signals derived from said last mentioned master counter stages, delaying means connected between said stage outputs and said reset means whereby said master counter stages to be reset are properly reset before said actuating signal disappears.
 37. The structure claimed in claim 26 including interfacing means between said strategy logic and said machine functions.
 38. The structure claimed in claim 26 wherein said control logic is implemented in the form of an MOS integrated circuit.
 39. The structure claimed in claim 38 including interfacing means between said MOS integrated circuit and said machine functions.
 40. The structure claimed in claim 39 wherein some at least of said interfacing means comprise bidirectional thyristors which are triggered into conduction directly from said MOS integrated Circuit.
 41. The structure claimed in claim 26 including means for bypassing at least one of said stages of said master counter.
 42. The structure claimed in claim 41 wherein said means for bypassing at least one of said stages of said master counter depends in part at least for its activation on the state of at least one of the succeeding stages in said master counter.
 43. The structure claimed in claim 1 wherein said master counter is separated into a frequency divider and an events register, the output of said frequency divider being connected to the input of said events register such that said events register advances its state by one each time said output of said frequency divider exhibits a logical one-zero transition, said frequency divider having a period at least equal to the duration of the longest event of said control strategy, said events register having a number of unique states at least equal to the maximum number of events in any of said cycles of said control strategy, said decoding logic having a separate output corresponding to each separate event of said control strategy such that a logical one appears at a given output of said decoding logic only during the state of said events register corresponding to that output of said decoding logic, period control logic for shortening the period of said frequency divider, said period control logic having inputs and outputs, period select logic for selecting the desired period for said frequency divider, said period select logic having inputs and outputs, said stages of said frequency divider having reset inputs, said outputs of said period control logic being connected to selected reset inputs of said frequency divider stages, outputs of said period select logic being connected to inputs of said period control logic, some at least of said outputs of said decoding logic being connected to said inputs of said period select logic such that for each state of said events register the period of said frequency divider is of the proper duration for the event corresponding to that state.
 44. The structure claimed in claim 43 wherein said function-control logic comprises a plurality of multiple-input function-control gates, said function-control gates being equal in number to said machine functions, the output of each of said function-control gates being connected to its respective machine function, some at least of said outputs of said decoding logic being connected to said inputs of said function-control gates such that the proper machine functions are activated during the event corresponding to each output of said decoding logic.
 45. The structure claimed in claim 43 wherein said control strategy comprises one or more cycles made up of a plurality of sequential operations, the preponderance of said operations comprising the same series of repeated events, said events register being separated into a first group of stages comprising a repeated events register and a second group of stages comprising an operations register, said repeated events register having exactly one state for each of said repeated events, said operations register having a unique state for each operation in the longest one of said cycles capable of being performed by said appliance, the output of said repeated events register being connected to the input of said operations register such that said operations register advances its state by one each time said repeated events register advances through the complete series of its states, said decoding logic being separated into first and second parts, said first part having a separate output for each state of said repeated events register, said second part having a separate output for each state of said operations register corresponding to an operation of said control strategy, the inputs of said first and second parts of said decoding logic being so connected to the outputs of said stages of said repeated events register and said operations register respectively that at any given timE there will simultaneously be a logical one at exactly one of said outputs of said first part and exactly one of said outputs of said second part of said decoding logic.
 46. The structure claimed in claim 45 including preset means coupled to said master counter by which a predetermined number of said stages of said master counter may be made to instantly selectively assume logical one or logical zero.
 47. The structure claimed in claim 45 wherein said appliance comprises a dishwashing machine.
 48. The structure claimed in claim 45 including means responsive to a signal from a source external of said means and interposed between said pulse source and said master counter to interrupt the transmission of pulses from said pulse source to said master counter for the duration of said signal, thereby inhibiting any change in state of said master counter for the duration of said signal.
 49. The structure claimed in claim 45 including means responsive to a signal from a source external of said means and connected to said pulse source to interrupt the transmission of pulses from one stage of said master counter to the next stage of said master counter for the duration of said signal, thereby inhibiting any change in state of said next stage and any succeeding stages of said master counter for the duration of said signal.
 50. The structure claimed in claim 45 including reset means coupled to said master counter by which a predetermined number of said stages of said master counter may be instantly selectively reset to logical zero.
 51. The structure claimed in claim 45 wherein said control logic is implemented in the form of a MOS integrated circuit, interfacing means between said MOS integrated circuit and said machine functions, some at least of said interfacing means comprising bidirectional thyristors controlled directly by said MOS integrated circuit.
 52. The structure claimed in claim 45 wherein said period control logic comprises means to immediately reset a predetermined number of stages of said frequency divider to logical zero, said reset means being connected to outputs of some at least of said stages of said frequency divider whereby said reset means generates a reset signal in response to signals from said last mentioned stages of said frequency divider to shorten the period of said frequency divider, delay means responsive to said reset signal for properly resetting said frequency divider stages before said actuating signal disappears.
 53. The structure claimed in claim 45 wherein said period control logic comprises means for bypassing at least one of said stages of said frequency divider.
 54. The structure claimed in claim 53 wherein said means for bypassing said at least one of said stages of said frequency divider is actuated in part at least by the state of at least one of the succeeding stages of said master counter.
 55. The structure claimed in claim 45 including a source of power for said control logic comprising a non-inductive DC power supply providing a first voltage and a second voltage, and means for delaying the establishment of said second voltage with respect to the establishment of said first voltage.
 56. The control system of claim 45 including a source of AC line current, said pulse source comprising a circuit means to attenuate and rectify said line current, a master switch, said pulse source being connected to said source of line current through said master switch, interfacing means in said connections between some at least of said machine functions and the outputs of said function-control logic, said source of line current comprising a source of power for said some at least of said machine functions via said master switch and said interfacing means, a DC power supply connected to said source of line current through said master switch, said DC power supply comprising a source of power for said control logic.
 57. The structure claimed in claim 56 including a safety switch in saId connections between said master switch and said pulse source and between said master switch and said machine functions.
 58. The structure claimed in claim 45 including a source of power for said control logic comprising a DC power source, at least one of said machine functions comprising a high current machine function, a source of AC voltage comprising a power source for said high current machine function, interfacing means connected between said high current machine function and its respective function-control logic output, said interfacing means comprising a high current bidirectional thyristor and a low current sensitive-gate bi-directional thyristor, said high current machine function being connected to said AC source via said high current bidirectional thyristor, the gate of said high current thyristor being connected to the load terminal of said low current thyristor, the gate of said low current thyristor being connected to said last mentioned function-control logic output.
 59. The structure claimed in claim 58 wherein said control logic is implemented in the form of an MOS integrated circuit, said triac being controlled directly by said MOS integrated circuit.
 60. The structure claimed in claim 43 including preset means coupled to said master counter by which a predetermined number of said stages of said master counter may be made to instantly selectively assume logical one or logical zero.
 61. The structure claimed in claim 60 wherein said preset means is connected to outputs of some at least of said master counter stages to be preset whereby said preset means is activated by signals derived from said last mentiond master counter stages, delaying means between said stage outputs and said preset means whereby said master counter stages to be preset are properly preset before said actuating signal disappears.
 62. The structure claimed in claim 43 wherein said appliance comprises a dishwashing machine.
 63. The structure claimed in claim 43 including means responsive to a signal from a source external of said means and interposed between said pulse source and said master counter to interrupt the transmission of pulses from said pulse source to said master counter for the duration of said signal, thereby inhibiting any change in state of said master counter for the duration of said signal.
 64. The structure claimed in claim 43 including means responsive to a signal from a source external of said means and interposed between said pulse source and said master counter to interrupt the transmission of pulses from one stage of said master counter to the next stage of said master counter for the duration of said signal, thereby inhibiting any change in stage of said next stage and any succeeding stages of said master counter for the duration of said signal.
 65. The structure claimed in claim 43 including reset means coupled to said master counter by which a predetermined number of said stages of said master counter may be instantly reset to logical zero.
 66. The structure claimed in claim 65 wherein said reset means is connected to outputs of some at least of said master counter stages to be reset whereby said reset means is actuated by signals derived from said last mentioned master counter stages, delaying means between said stage outputs and said reset means whereby said master counter stages to be reset are properly reset before said actuating signal disappears.
 67. The structure claimed in claim 43 including interfacing means between said strategy logic and said machine functions.
 68. The structure claimed in claim 43 wherein said control logic is implemented in the form of an MOS integrated circuit.
 69. The structure claimed in claim 68 including interfacing means between said MOS integrated circuit and said machine functions.
 70. The structure claimed in claim 69 wherein some at least of said interfacing means comprises bidirectional thyristors which are triggered into conduction directly from said MOS integrated circuit.
 71. The structure claimed in claim 43 including means for bypassing at least one of said stages of said master counter.
 72. The structure claimed in claim 71 wherein said means for bypassing at least one of said stages of said master counter depends in part at least for its activation on the state of at least one of the succeeding stages in said master counter. 